Prints having a toner or ink overcoat, particularly a clear overcoat, are often desired for such printed products as business cards, invitations, and placards due to their aesthetically pleasing texture. Also, such prints are often equated with high-quality and luxury. Several approaches for overcoating images with clear toner or ink, including “thermography” or “thermographic printing,” have been developed.
In one example of thermographic printing, a base image on media is purposely left uncured or fused, creating a “wet” surface on the image serving as a tacking layer. As the process proceeds, a powder or dry substrate is applied to the “wet” surface of the image, resulting in the powder adhering to the image. A vacuum process is applied to remove any loose or residual powder off the media surface. The media, with the image thereon, is then transferred into a heating apparatus (such as an oven) where a transition occurs. The dry powder is turned into a molten state and is allowed to cure and solidify. The end result is a raised textured surface mapped over the image known as a thermographic print.
Thermographic printing is a cumbersome, hardware intensive process, requiring numerous operational steps to produce a thermographic image. This results in run costs that are considerably higher than those encountered in digital printing. High cost is attributable to, among other things, the lack of inline printing operations, the high demand for skilled labor and energy, as well as the need for multiple machines.
Another approach for overcoating can be found in xerographic printers employing clear toner. For instance, U.S. Pat. No. 7,212,772 discloses an electrophotographic printer configured to print a three-dimensional texture on a substrate by applying clear toner in locations corresponding to where texture is desired. The clear toner for texture may be applied either after, or before, other colors (e.g., CMYK) are applied to the substrate.
An electrophotographic printing system may include a front-end station for scanning a document coupled to an electrophotographic printer to permit an operator to add texture during the reproduction of the scanned document.
Although the xerographic print system discussed above with respect to U.S. Pat. No. 7,212,772 provides a process for adding texture to a xerographic print, U.S. Pat. No. 7,212,772 does not add texture to a pre-existing, rendered print, wherein a rendered print typically includes either (1) a rendered xerographic print, the rendered xerographic print being a substrate having toner, forming an image, fused thereon, or (2) a rendered ink print, the rendered ink print being a substrate having ink, forming an image; dried thereon.
Therefore, it is desirable to provide a printing system that enables the addition of texture to a pre-existing, rendered print.